1. Field of the Invention
The present invention relates in general to drug delivery devices used to deliver ionic medicaments through the skin or other tissues, and, more particularly, to fluid assemblies and electrode assemblies for the release and delivery of a medicament to a patient.
2. Background Art
Drug delivery devices have been known in the art for a number of years. Furthermore, drug delivery devices having fluid delivery assemblies for delivering fluid to bioelectrodes are likewise well known. Conventional fluid delivery assemblies have utilized a number of methods for the release and delivery of a fluid. These methods include rupturing one or more pouches contained within a rigid or semi-rigid container, or having a number of microcapsules within a porous membrane that, when ruptured, release a fluid through the membrane. These methods include a number of drawbacks, including the necessity for several separate structures, and the additional and sometimes cumbersome structures necessary to direct the flow of the released fluid.
Iontophoretic drug delivery devices, a subset of drug delivery devices, have also been known in the art for some time. These devices provide the electromotive force that drives an ionic drug from a pad or sponge containing the drug through the skin or other surface of a patient. Conventional drug delivery devices generally include a single active electrode and a single passive electrode, completing the circuit once the two are attached to the tissue of a patient. However, this electrode alignment has the drawback of requiring either high electric fields to deliver sufficient drug to the area, resulting in unwanted sensation and burning, or lower electric fields and resultantly lower delivery rates of the drug. Therefore, the use of a single set of an active and a passive electrode often results in unwanted electric field concentration or in decreased electrode performance.
The conventional iontophoretic devices additionally utilize well known methods of retaining a medicament in the drug delivery device, including gel sponges and disbursement pads. These media retain a medicament until placed next to skin/tissue and subjected to an electric current. However, these media can leak or seep fluid once applied, causing a short-circuit of the entire device.
It is therefore an object of the present invention to provide a simple and effective means for releasing a fluid from a reservoir, and then directing the flow of that fluid in a predetermined direction.
It is a further object of the present invention to provide consistent and optimum iontophoretic delivery of a drug while minimizing the negative effects of a concentrated electric field.
It is additionally an object of the present invention to provide a simple and effective structure for the prevention of migration of the medicament in the device out of the delivery pad towards the passive electrode.
It is also an object of the present invention to provide an integrated device and method, utilizing the above advantages, for the delivery of a fluid to a drug delivery device, and then to the tissue of a patient, while maintaining the integrity of the electrodes and the medicament.
These and other objects of the invention will be apparent to those having ordinary skill in the art in light of the associated specification, claims and drawings.